Brussels, Belgium: Belgian prosecutors said Thursday they were looking for further suspects in an emerging terror investigation and feared a possible fresh attack as the country remained on high security alert.

"We are still looking for several terrorism suspects," Eric van der Sypt, the spokesman for the federal prosecutors' office, told VTM television. "We fear they may feel cornered. We therefore fear there could be the same reaction as on March 22 (2016)," he said.

The ongoing search follows the discovery of a stash of weapons in a Brussels suburb, including Kalashnikov assault rifles, smaller firearms, ammunition, bullet proof vests, detonators, a blue police beacon and security and police uniforms. The items found in a lock-up garage sparked concern that potential attackers could have been plotting to pose as police and other officials.

Police charged two brothers of a convicted jihadist on Wednesday but revealed on Thursday they are looking for further members of a possible terror cell. Belgian nationals Akim and Khalid Saouti, who were among four people detained in overnight raids on Tuesday, are believed to be the brothers of Said Saouti, a member of the Kamikaze Riders motorcycle club. The Kamikaze club is a Moroccan outfit, with form for jihadist connections. Why Hells Angels Europe have tolerated them I don't know.

They were charged on Wednesday with belonging to a "terrorist group" and suspected of planning an attack.

Last year, Said was jailed for recruiting people to jihadist organisations and supporting IS on social media.

A spokesman for prosecutors had said earlier that the raids were "directly linked" to members of the Kamikaze Riders, not to the investigation into the Paris and Brussels attacks.